Many electronic devices (e.g., including electronic circuitry) generate heat during operation. Heat generated by electronic devices is preferably dissipated so as to improve reliability and reduce the potential for premature failure of the electronic devices. In some instances, the amount of heat generated by an electronic device may be such that cooling of the device by a heat transfer system is necessary to prevent overheating.
One proposed approach for dissipating heat generated by electronic devices is the use of a two-phase heat transfer system. In a two-phase heat transfer system, an evaporator may receive heat from an electronic device resulting in the heating of a fluid contained by the evaporator. In this regard, the fluid may undergo a phase change (e.g., the fluid may be vaporized from a liquid to a vapor). In turn, the evaporator may be connected to a condenser by way of a pipe or other plumbing extending between the evaporator and the condenser. Once the vaporized fluid enters the condenser, heat may be transferred from the fluid to the environment by way of the condenser such that the fluid condenses into a liquid in the condenser. In this regard, the condensed fluid in the liquid phase may be returned to the evaporator by the pipe extending between the condenser and the evaporator. Accordingly, the liquid phase fluid may again be heated in the evaporator and the cycle may repeat.
Two-phase heat transfer system may be beneficial because the amount of thermal energy (i.e., heat) associated with latent energy of a phase change is greater than a sensible heat of the fluid alone. That is, when a material undergoes a phase change the latent heat associated with the phase change of the material is absorbed or released in addition to the sensible heat associated with the change in temperature of the material in a single phase. Thus, a fluid that is transported after undergoing a change in phase may include significantly more energy than a fluid that has undergone sensible heating alone. It may often be the case that the latent heat associated with the phase change is much greater than the sensible heat that may be absorbed by the material.
Some two-phase heat transfer systems employ a pump or compressor to move the fluid through the cycle. It has also been proposed that capillary force, a pressure drop, or gravitational forces may be used to move the fluid through the cycle in a two-phase heat transfer system. In this regard, traditional two-phase heat transfer systems may be susceptible to a plurality of failure modalities that may negatively impact the reliability of the heat transfer system. For example, in the case of a two-phase heat transfer system that relies on a pump or the like to move fluid through the system, failure of the pump may render the system inoperable. Furthermore, the use of pipes or other plumbing to direct the fluid in the system (e.g., as in the case of a loop heat pipe) may be susceptible to failure, thus resulting in leaks and/or the reduction in fluid flow in the system. In any regard, the effectiveness of the system may be reduced or the system may undergo complete failure, which may result in undesirable excessive heating of the electronic device cooled by the heat transfer system.